Just got back from DS's doc and he is 39 inches at 2.5 years old. He has 1 inch left RFing on his CA65! If he stays on his current growth curve he will be out of it in 4 months. I was really hoping to keep him rfing through 3 enough that I want to buy him a new seat (especially since we will be in a snow/icey place this winter).

You may want to look at the new Graco Size4Me70. There is no RFing height limit. As long as the top of the head is 1" below the top of the headrest and harness height is at or below shoulders, it can be RFing. The headrest can be used at all heights RFing. There is a 40lbs weight limit for RFing on this seat. Looks like this thread on car-seat.org has a comparison of the Graco and the CA65. http://www.car-seat.org/showthread.php?t=230508

The True Fit and Size4Me would both be great choices, as they are both very tall and use the 1" rule. I hate the 40" total height limit on the Complete Air, because it does have a tall shell.

For seated heights, you may look at this:https://sites.google.com/site/carseatmeasurements/
It's put together by a member at Car-seat.org, and uses member-submitted data. I don't know if the S4M is on there yet, but that info should be in the links above if not.

I hate the 40" total height limit on the Complete Air, because it does have a tall shell.

For seated heights, you may look at this:https://sites.google.com/site/carseatmeasurements/
It's put together by a member at Car-seat.org, and uses member-submitted data. I don't know if the S4M is on there yet, but that info should be in the links above if not.

That 40 inch rule is seriously frustrating. He has so much more room in that seat, but apparently its unusable. Thanks for the link!

Honestly, and I'm not recommending anything here, but if I had a long-legged child who had lots of room above his or her head in the CA, I would probably be willing to overlook the 40" overall height limit.

Size limits have a lot to do with the sizes and weights and heights of crash test dummies. The rules which govern which crash test dummy has to pass with which seat based on what the stated limits are, are convoluted and confusing. I can't even begin to summarize it accurately here. But basically if there's a dummy that is, say (pulling numbers out of my hat here), 41" tall and weighs 55 lbs, a car seat that allows for a 41" crash test dummy has to pass testing even though the dummy is 15 lbs over the weight limit. I do not know the actual sizes and weights of the dummies used to test the seats, but I can see why manufacturers sometimes put seemingly arbitrary limits on car seats which may or may not translate into this or that real-world kid.

As it happens, my daughter is longer in the torso than in the legs, and just making a guess based on how tall she is in the CA right now at 36" tall, my guess is she'll be pretty close to "actually" outgrowing the seat when she hits 40" anyway. So my current plan is to go ahead and abide by the 40" rule. But if I had a leggy kid I think I'd feel OK ignoring it.